Is there any academic research on the psychology of charitable
donations?

I would like to know, for instance, whether people are more likely to
donate money to a cause or program if there is a cap on donations.  Is
there a change in a person's willingness to donate based on the base
level of a donation?  Are people more likely to donate to a program
where they have some sort of input into its implementation?

The previous questions don't need to be answered.  I just want to know
where I can find the answers to these types of questions.  For
instance, have there been any recent journal articles or books written
on the subject?  If so, where would I find these?

Thanks to anyone who attempts to answer this quesion!

Here's a description of a book that might be of interest:

http://www.smu.edu/newsinfo/releases/00148.html

This website contains a wealth of information:

http://www.charitychannel.com/